JP2001056010A - Bolt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bolt capable of securing connecting precision of a plural number of members to be fastened by the bolt and miniaturizing parts without causing cost increase and lowering of production performance. SOLUTION: A press-fitting part 13 having a head part 11 on one end, a screw part 12 to screw a nut 4 in it on the other end and having an outside diameter larger than a diameter of bolt insertion holes 21 along a plural number of the bolt insertion holes 21 of a member to be fastened in a state where fastening is completed on a shaft part between the head part 11 and the screw part 12 which is provided on a bolt 1 to fasten a plural number of the members to be fastened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bolt for fastening a plurality of members to be fastened.

[0002]

In a camshaft of an automobile, a bracket is attached to an engine body, a camshaft hole is machined, a bracket is removed, a camshaft is attached, and a bracket is reassembled to attach the engine body to the engine body. It is pinched by. The bracket and the engine body are fastened with bolts.

[0003] In the case of a crankshaft, the lower end of the connecting rod is divided into two parts, and the divided bodies are fastened to each other by bolts with the crankshaft interposed therebetween.

As described above, when two members, such as the engine body and the bracket, the divided bodies of the connecting rods, etc., are fastened by bolts, the method shown in FIG. 3 has conventionally been used. FIG. 3 shows a case where the members to be fastened a and b are fastened with bolts c.
The outer peripheral surface of the shaft portion d of the bolt c and the insertion hole e of the member a to be fastened
Since it is necessary to secure a gap required for insertion between the inner peripheral surface and the inner peripheral surface, the shaft center between the insertion hole e of the member a and the screw hole f of the member b is displaced at the time of fastening, and a predetermined coupling accuracy is obtained. It is not possible to secure. Therefore, in the case of the above-described camshaft and the like, it causes friction and abnormal noise.

Therefore, conventionally, the press-fit ring g is fitted into an annular groove h formed around the screw hole f of the member b to be fastened, and is formed around the insertion hole e of the member a to be fastened. By press-fitting the annular groove i into the press-fit ring g, the joining accuracy of the two members a and b was ensured.

However, as described above, a press-fit ring g
And opening the grooves h and i complicate the manufacturing process and structure, resulting in high cost and lower production efficiency. Further, the necessity of securing the mounting space of the press-fit ring g makes it difficult to reduce the size of parts.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is possible to secure the coupling accuracy of a plurality of members to be fastened by bolts, and to cause a high cost and a decrease in production efficiency. It is another object of the present invention to provide a bolt that can reduce the size of parts without using the same.

[0008]

According to the present invention, there is provided a bolt for fastening a plurality of members to be fastened, wherein a head is screwed at one end and a nut is screwed at the other end. And a shaft portion between the head portion and the screw portion, the bolt portion having a larger diameter than the diameter of the bolt insertion hole over the bolt insertion holes of the plurality of members to be fastened in a state where the fastening is completed. Characterized in that a press-fit portion having a diameter is provided,
Provide bolts.

In the above-mentioned bolt, the press-fitting portion is formed by forming irregularities on the peripheral surface of the shaft portion, providing a threaded portion on the peripheral surface of the shaft portion, and adjusting the crest diameter of the screw insertion hole of the member to be fastened. Characterized in that it is formed larger than the diameter, the axial surface is provided with a selection on the peripheral surface of the shaft portion, and the mountain diameter is formed larger than the diameter of the bolt insertion hole of the member to be fastened. Provide bolts. Further, the present invention provides a bolt wherein the thread diameter of the screw portion is smaller than the outer diameter of the press-fit portion. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0010]

First Embodiment As shown in FIG. 1, a bolt 1 of the present invention has a head 11 at one end and a screw portion 12 for screwing a nut 4 at the other end. A press-fit portion 13 is provided on a shaft portion between the screw portion 12 and the screw portion 12.

In the state where the fastening is completed, the press-fitting portion 13 includes a plurality of members to be fastened, in FIG.
The three bolt insertion holes 21 and 31 have outer diameters larger than the diameters of the bolt insertion holes 21 and 31.

In the present embodiment, the press-fitting portion 13 includes a thick shaft portion 14.
The thread diameter of the screw is formed slightly larger than the diameter of the bolt insertion holes 21 and 31.

Then, by cutting the inner peripheral surfaces of the bolt insertion holes 21 and 31 by the press-fitting portion 13, the axes of the bolt insertion holes 21 and 31 are forcibly aligned, thereby ensuring accurate coupling accuracy. Can be.

In this embodiment, the bolt has a thick shaft portion 14 and a thin shaft portion 15, and the press-fit portion 13 is provided in a part of the thick shaft portion 14. The thick shaft portion 13 may be provided over the entire length. It is also conceivable that the shaft portion of the bolt is formed to have the same diameter over the entire length, the press-fit portion 13 is provided over the entire length, and the screw portion 12 is also used.

The screw portion 12 is provided at a part of the distal end of the thin shaft portion 15 and has a ridge diameter of the press-fit portion 13 and the bolt insertion hole 2.
1, 31 are formed smaller than the diameter. In addition, the fine shaft portion 15
May be provided over the entire length of the thread.

[0016]

[Embodiment 2] The embodiment shown in FIG.
6 shows a case where the peak diameter is formed larger than the diameter of the bolt insertion holes 21 and 31.

Then, the inner peripheral surfaces of the bolt insertion holes 21 and 31 are plastically deformed by the press-fitting portion 16, whereby
The axes of the bolt insertion holes 21 and 31 are forcibly aligned, and accurate coupling accuracy can be ensured. In the case of such a selection shape, the bolt insertion holes 21, 31
Has a small contact area with the inner peripheral surface, so that frictional resistance is small and press-fitting can be easily performed.

In this embodiment, the press-fit portion 16 is provided over the entire length of the thick shaft portion 14. However, the press-fit portion 16 is formed only in a partial area such as the press-fit portion 13 shown in FIG. I think

[0019]

Embodiment 3 As another shape of the press-fitting portion,
Although not shown, it is also conceivable to form irregularities on the peripheral surface of the shaft portion by shot peening or the like, or it may be a press-fitted portion having a screw, a selection, or a smooth surface without irregularities.

[0020]

Since the present invention has been described above,
The following effects can be obtained. <B> Bolts are fastened by plastically deforming or cutting the inner peripheral surfaces of the bolt insertion holes of the plurality of members to be fastened by the press-fit portions provided on the shaft portions of the bolts. Therefore, when plastic deformation or cutting is performed, the axes of the bolt insertion holes of the plurality of members to be fastened are forcibly aligned, and accurate coupling accuracy can be secured.

<B> Since there is no need to form an annular groove and use a separate press-fit ring as in the conventional case, it is possible to reduce costs, improve production efficiency, and reduce the number of parts. Can also reduce the size of parts.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of Embodiment 1 of the present invention.

FIG. 2 is an explanatory diagram of Embodiment 2 of the present invention.

FIG. 3 is an explanatory view of a conventional technique.

Claims (5)

[Claims] 1. A bolt for fastening a plurality of members to be fastened, comprising a head at one end and a screw portion at the other end for screwing a nut, and a shaft between the head and the screw portion. A bolt provided with a press-fit portion having an outer diameter larger than the diameter of the bolt insertion hole over the bolt insertion hole of the plurality of members to be fastened in a state where the fastening is completed. 2. The bolt according to claim 1, wherein the press-fit portion is formed by forming irregularities on a peripheral surface of the shaft portion. 3. The bolt according to claim 1, wherein the press-fitting portion is provided with a threaded portion on a peripheral surface of the shaft portion, and a diameter of the threaded portion is formed larger than a diameter of the bolt insertion hole of the member to be fastened. Characterized by bolts. 4. The bolt according to claim 1, wherein the press-fit portion is provided with a selection in an axial direction on a peripheral surface of the shaft portion,
A bolt having a peak diameter larger than a diameter of a bolt insertion hole of a member to be fastened. 5. The bolt according to claim 1, wherein a thread diameter of the screw portion is smaller than an outer diameter of the press-fit portion.